Convert Go example into multi-stage Docker build

Reducing dependencies to working with the examples,
this has been converted into a multi stage Docker build.

This also removes the client, as nobody is using it,
as netcat works perfectly.

Author: markmandel

examples/simple-udp/server/Dockerfile examples/simple-udp/Dockerfileexamples/simple-udp/server/Dockerfile renamed to examples/simple-udp/Dockerfile

@@ -12,12 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# build
+FROM golang:1.10.3 as builder
+WORKDIR /go/src/simple-udp
+
+COPY examples/simple-udp/main.go .
+COPY . /go/src/agones.dev/agones
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o server .
+
+# final image
 FROM alpine:3.7
 
 RUN adduser -D server
-
-COPY ./bin/server /home/server/server
-    
+COPY --from=builder /go/src/simple-udp/server /home/server/server
 RUN chown -R server /home/server && \
     chmod o+x /home/server/server
 

examples/simple-udp/Makefile

@@ -28,7 +28,7 @@ REPOSITORY = gcr.io/agones-images
 mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
 project_path := $(dir $(mkfile_path))
 server_tag = $(REPOSITORY)/udp-server:0.3
-package = agones.dev/agones/examples/simple-udp
+root_path = $(realpath $(project_path)/../..)
 
 #   _____                    _
 #  |_   _|_ _ _ __ __ _  ___| |_ ___
@@ -37,19 +37,6 @@ package = agones.dev/agones/examples/simple-udp
 #    |_|\__,_|_|  \__, |\___|\__|___/
 #                 |___/
 
-# build both client and server
-build: build-server build-client
-
-# Build the server
-build-server:
-	CGO_ENABLED=0 go build -o $(project_path)/server/bin/server -a -installsuffix cgo $(package)/server
-
 # Build a docker image for the server, and tag it
-build-server-image:
-	docker build $(project_path)/server/ --tag=$(server_tag)
-
-# Build the client
-build-client:
-	go build -o $(project_path)/client/bin/client $(package)/client
-
-
+build:
+	cd $(root_path) && docker build -f $(project_path)/Dockerfile --tag=$(server_tag) .

examples/simple-udp/README.md

@@ -1,6 +1,6 @@
 # Simple UDP Server
 
-A very simple UDP logging server and client, for the purposes of demoing and testing
+A very simple UDP logging server, for the purposes of demoing and testing
 running a UDP based server on Agones.
 
 ## Server
@@ -10,7 +10,5 @@ When it receives a text packet, it will send back "ACK:<text content>" as an ech
 
 If it receives the text "EXIT", then it will `sys.Exit(0)`
 
-## Client
-Client will read in from stdin and send each line to the server.
-
-Address defaults to `localhost:7654` but can be changed through the `address` flag.
+To learn how to deploy your edited version of go server to gcp, please check out this link: [Edit Your First Game Server (Go)](../../../docs/edit_first_game_server.md),
+or also look at the [`Makefile`](./Makefile).

examples/simple-udp/client/main.go

@@ -1,4 +1,4 @@
-// Copyright 2017 Google Inc. All Rights Reserved.
+// Copyright 2018 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.